Poly(ADP-ribose)polymerase (abbreviated as PARP hereinafter), which is a nuclear enzyme activated by DNA strand breaks, plays a role in the transfer reaction of ADP-ribose moiety from nicotinamide adenine dinucleotide (abbreviated as NAD+ hereinafter) to various proteins such as histones, DNA-polymerases and DNA-topoisomerases, etc.
DNA strand breaks caused by Peroxynitrite (ONOO−) and oxygen radicals lead to overactivation of PARP (PARP is activated up to 100 times when Zn finger domain of PARP binds to DNA with nicks.). It is thought that overactivation of PARP causes depletion of NAD+, which is essential for electron transport system, and consequently depletion of ATP, leading to energy failure, ultimately resulting in cell death. (The suicide hypothesis of PARP activation: Free Radic. Biol. Med., 21, 855 (1996); TIPS., 19, 287 (1998)). Therefore, it is considered that PARP inhibitor is useful as inhibitor of cell death.
Since caspase-3, which is one of interleukin-1β-converting enzyme family, specifically cleaves PARP as the substrate (Cell., 81, 801 (1995)), it is suggested PARP is associated with apoptosis.
It is reported that 3-aminobenzamide and nicotinamide generally known as inhibitors of PARP are useful for inhibition of cell death and improvement of diseases on various models of ischemic diseases (cerebral, myocardial, intestinal, skeletal muscular or retinal ischemia etc.), inflammatory diseases (arthritis, inflammatory bowel disease or multiple sclerosis etc.), diabetes, shock, extrapyramidal disease (TIPS., 19, 287 (1998); Eur. J. Pharmacol., 350, 1 (1998)) and hyperalgesia (Pain, 72, 355 (1997)) in vitro, in vivo and in PARP knockout mouse. And it is reported that PARP inhibitor is useful as an antiretroviral drug such as an anti HIV drug (Biochem. Biophys. Res. Commum., 180, 504 (1991)), a sensitizer of anticancer therapy (Radiat. Res., 126, 367 (1991); Br. J. Cancer., 72, 849 (1995)) or an immunosuppressant (Int. J. Immunopharmac., 17, 265 (1995)).
PARP inhibitor is useful for prevention and/or treatment of various diseases, for example, ischemic diseases (cerebral infarction, myocardial infarction, reperfusion injury or postoperative injury etc.), inflammatory diseases (inflammatory bowel disease, multiple sclerosis, arthritis or lung injury etc.), neurodegenerative disorders (extrapyramidal disease, Parkinson's disease, Alzheimer's disease, muscular dystrophy or lumbar spinal canal stenosis etc.), glaucoma, diabetes, diabetic complication, shock, head trauma, spinal cord injury, renal failure, hyperalgesia or blood flow obstruction etc. And it is useful as an antiretroviral drug such as an anti HIV drug, a sensitizer of anticancer therapy or an immunosuppressant.
As PARP inhibitor, for example, in the specification of WO00/44726, it is described that 2H-phthalazin-1-one derivatives represented by formula (A)
(wherein R1A is    (i) C1-4 alkyl substituted by hydroxy or amino, or    (ii) -A1A-A2A-A3A,in which A1A is —NR3AC(O)— etc. wherein R3A is hydrogen or C1-4 alkyl etc., A2A is C1-8 alkylene etc., A3A is (i) hydrogen, (ii) —NR17AR18A or (iii) Cyc2A etc. wherein R17A is (i) hydrogen, (ii) C1-8 alkyl etc., and R18A is (i) hydrogen or (ii) C1-8 alkyl etc., Cyc2A is 3-10 membered mono- or bi-heterocyclic ring containing 1-4 of nitrogen atoms, 1-2 of oxygen atoms and/or one sulfur atom, R2A is hydrogen or halogen etc. Necessary parts were extracted from the description of groups.) have PARP inhibitory activity.
In the specification of DE3302021, it is described that compounds represented by formula (B)
(wherein R1B is hydrogen or C1-3 alkyl, R2B is hydrogen, R1B and R2B, taken together, are C1-4 alkylene, R3B is hydrogen or methyl, nB is 0-3, R4B is 1-pyrrolyl. Necessary parts were extracted from the description of groups.) have inhibitory activity of platelet aggregation.
In the specification of WO98/31674, it is described that compounds represented by formula (C)
(wherein R1C is C1-4 alkoxy etc., R2C is C1-8 alkoxy etc., R3C and R4C is hydrogen or R3C and R4C, taken together, are bond, R5C is hydrogen etc. Necessary parts were extracted from the description of groups.) have phosphodiesterase inhibitory activity.
In Journal of Medicinal Chemistry., 44(16), 2511-2522 and 2523-2535 (2001), it is described that 4-(3-chloro-4-methoxyphenyl)-4a,5,8,8a-tetrahydrophthalazin-1(2H)-one (CAS Registry No. 244077-36-9) and 4-(3,4-dimethoxyphenyl)-5,6,7,8-tetrahydrophthalazin-1(2H)-one (CAS Registry No. 358368-98-6) have phosphodiesterase inhibitory activity.
In Tetrahedron., 39(20), 3419-27 (1983), 4-phenyl-6,7,8,8a-tetrahydropyrrolo[1,2-d][1,2,4]triazin-1(2H)-one (CAS Registry No. 89311-30-8) is described as synthetic intermediate.
In Synthesis., 240-242 (1995), 4-phenyl-5,6,7,8-tetrahydrophthalazin-1(2H)-one (CAS Registry No. 154810-22-7), 4-(4-methylphenyl)-5,6,7,8-tetrahydrophthalazin-1(2H)-one (CAS Registry No. 154810-23-8), 4-(4-fluorophenyl)-5,6,7,8-tetrahydrophthalazin-1(2H)-one (CAS Registry No. 154810-24-9), 4-(4-chlorophenyl)-5,6,7,8-tetrahydrophthalazin-1(2H)-one (CAS Registry No. 154810-25-0), and 4-(4-bromophenyl)-5,6,7,8-tetrahydrophthalazin-1(2H)-one (CAS Registry No. 154810-26-1) are described as synthetic intermediate.
In Bioorganic and Medicinal Chemistry., 6, 349-454 (1998), 7-hydroxy-4-phenyl-6,7,8,8a-tetrahydropyrrolo[1,2-d][1,2,4]triazin-1(2H)-one (CAS Registry No. 206126-90-1) and 4-phenyl-8,8a-dihydro[1,3]thiazolo[3,4-d][1,2,4]triazin-1(2H)-one (CAS Registry No. 206126-96-7) are described as synthetic intermediate.
In Journal of Medicinal Chemistry., 43(12), 2310-2323 (2000), 4-(pyridin-4-ylmethyl)-5,6,7,8-tetrahydrophthalazin-1(2H)-one (CAS Registry No. 212142-89-7) is described as synthetic intermediate.
In the specification of FR2647676, 4-t-butoxycarbonylmethyl-5,6,7,8-tetrahydrophthalazin-1(2H)-one (CAS Registry No. 134972-12-6) and 4-ethoxycarbonylmethyl-5,6,7,8-tetrahydrophthalazin-1(2H)-one (CAS Registry No. 134973-24-3) are described as synthetic intermediate.